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Diffstat (limited to 'lib')
-rw-r--r--lib/rwsem.c17
1 files changed, 9 insertions, 8 deletions
diff --git a/lib/rwsem.c b/lib/rwsem.c
index edf3d9ca670e..0d50e46d5b0c 100644
--- a/lib/rwsem.c
+++ b/lib/rwsem.c
@@ -216,14 +216,15 @@ struct rw_semaphore __sched *rwsem_down_write_failed(struct rw_semaphore *sem)
/* wait until we successfully acquire the lock */
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
while (true) {
-
- /* Try acquiring the write lock. */
- count = RWSEM_ACTIVE_WRITE_BIAS;
- if (!list_is_singular(&sem->wait_list))
- count += RWSEM_WAITING_BIAS;
- if (cmpxchg(&sem->count, RWSEM_WAITING_BIAS, count) ==
+ if (!(count & RWSEM_ACTIVE_MASK)) {
+ /* Try acquiring the write lock. */
+ count = RWSEM_ACTIVE_WRITE_BIAS;
+ if (!list_is_singular(&sem->wait_list))
+ count += RWSEM_WAITING_BIAS;
+ if (cmpxchg(&sem->count, RWSEM_WAITING_BIAS, count) ==
RWSEM_WAITING_BIAS)
- break;
+ break;
+ }
raw_spin_unlock_irq(&sem->wait_lock);
@@ -231,7 +232,7 @@ struct rw_semaphore __sched *rwsem_down_write_failed(struct rw_semaphore *sem)
do {
schedule();
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
- } while (sem->count & RWSEM_ACTIVE_MASK);
+ } while ((count = sem->count) & RWSEM_ACTIVE_MASK);
raw_spin_lock_irq(&sem->wait_lock);
}